Female Jewish and Muslim MPs are the top target of increased threats and abuse on social media, according to the Deputy Speaker of the House of Commons.
Lindsay Hoyle warned the worrying development was damaging democracy and could deter women from these communities from entering politics.
He also called on social media companies to react faster to offensive posts or face possible legal action.
Mr Hoyle was giving evidence to the Home Affairs Select Committee - and he confirmed Parliament had set up a team to monitor abuse online and to provide support to those affected.
The Select Committee is investigating hate crime in the wake of the murder of Labour MP Jo Cox last year.
Giving evidence Mr Hoyle confirmed female Jewish and Muslim MPs received more threats than men – particularly from far-left and far-right sympathisers.
As chair of Parliament’s consultative panel on security he said the situation “undermines democracy” because MPs had to be concerned about carrying on meeting members of the public.
"General banter is fine. But it's about the level. Robust debate is good, but when that says, 'I'm going to come round and kill you,' that is more serious," said the Deputy Speaker.
Jewish Labour MPs Luciana Berger and Ruth Smeeth are among those to be targeted by online threats and abuse in recent years. Muslim MP Tulip Siddiq also revealed she had received death threats.