The former deputy prime minister is also due to address private meetings of MEPs and will call on them to try to delay the Brexit divorce process.
A spokesman for Mr Clegg said: “As it is now clear that any idea of a soft Brexit is dead, Nick will be encouraging his contacts across the EU to give the UK time to respond and negotiate if MPs reject whatever form of hard Brexit the government presents to parliament.”
This comes as Mr Clegg accused EU officials of fuelling Brexit with their “sneering disregard for the politics of identity and patriotism”.
He insisted MPs have a democratic duty to block Brexit, saying the UK will see none of the benefits the Leave campaigners claim.
He said he had “not given up hope” that on “the 59th second of the 11th hour” the split from Brussels will be stopped.
Last week Mr Verhofstadt said the rights of EU citizens were “not negotiable”.
He said: “Prime Minister May’s comments appear to be part of a domestic negotiation within the UK Cabinet, and threaten to increase existing uncertainties for citizens, which is regrettable.”
European Commission officials are expected to adopt a draft text of a chapter of the withdrawal agreement on transition as early as today.
The European Parliament president Antonio Tajani is the latest EU chief to hold out an olive branch to the UK.
The Italian MEP has said: “If the UK wants to change its position on Brexit, we are happy with that.”
These comments come after European Council president Donald Tusk and his European Commission counterpart Jean-Claude Juncker said they would welcome the UK back to the EU.
Mr Tajani said the Brexit divorce bill should be “at least €60billion (£53.2bn)” in a shock statement.
In November, he said that even the British Government was becoming disillusioned with Brexit.