Speaking after the meeting Mrs May said party leaders also agreed to upgrade an existing complaints hotline to a face-to-face human resources service.
The latter will be introduced by the end of the month and the new grievance procedure should be in place in next year, Mrs May told reporters.
Mrs May said the agreement was an 'important step forward' following the talks in Parliament as a sex scandal threatens to engulf politics.
The Prime Minister was sat face to face with Labour leader Jeremy Corbyn and was joined by politicians from the SNP, Liberal Democrats, Plaid Cymru, DUP and the Greens.
Even with the support of the DUP, Mrs May has a Commons majority of just 13, which would be wiped out if she lost seven seats.
One minister last night warned that the Tories were in 'no fit state to present ourselves to the electorate' and said the only consolation was 'neither are Labour'.
Labour's John Mann has said the scandal engulfing Westminster would lead to 'at least 12 by-elections'.
Theresa May (third right) and Jeremy Corbyn (third left) joined a meeting party leaders for emergency talks tonight (pictured) to try and toughen up protections for MPs' staff.
Also in attendance were (clockwise from left) SNP leader Ian Blackford, shadow women's minister Dawn Butler, Labour leader Jeremy Corbyn, leader's chief of staff Karie Murphy, Lib Dem leader Sir Vince Cable, Lib Dem deputy leader Jo Swinson, Plaid Cymru leader Liz Saville Roberts, Unknown Aide, Unknown Aide, DUP chief whip Geoffrey Donaldson, No 10 deputy chief of staff Joanna Penn, Prime Minister Theresa May, Commons Leader Andrea Leadsom, Lords Leader Natalie Evans Speaking after the meeting in her parliamentary office, Mrs May said: 'Sadly, over recent days, we have seen a number of allegations about figures from across the political parties and it's important that those are investigated impartially and some have rightly been referred to the police.'I think if this hasn't happened to you it's difficult to appreciate the impact that being a victim of this sort of behaviour can have, it simply has a lasting impact on people.'And we need to do more to stop these abuses of power and I'm pleased that having convened this meeting of party leaders today we have agreed a way forward.'We are going to ensure that there's an upgrade to the existing phone line for staff so that staff in future will be able to get face-to-face HR support and for that to be in place by the end of the month.'And we've also agreed that we need a completely new grievance procedure for staff working here, for everybody working here, and that that should come into effect in the New Year.'So I think an important step forward has been taken today, it's important that we get this right, and I'm sorry that we have seen these abuses of power - too many taking place over too many years.'And the fact that they have taken place here at our seat of democracy should be a matter of shame for us all.'Earlier today, Mrs May admitted that politicians on all sides had failed to tackle the 'deeply troubling' problems over many years.
That confusion led nurse Nina Pham, 26, to report to the hospital on Friday when she noticed a spike in her temperature.
Just four days later, her co-worker Miss Vinson, became the second nurse at the hospital to contract the disease.
'This is not a situation like the flu where the risks of a rapid spread of the disease are imminent.'But the president's confidence has been confounded by his choice of point-persons, which is under fierce attack on Capitol Hill as Republican members of Congress privately fret that the administration has put the wrong people out in front.