"I also welcome the appointment of Gavin Robinson as Interim Leader of the DUP"
Mr Heaton-Harris said he would use the trip to “champion Northern Ireland’s economic potential as a great place to trade, invest, visit and study”
Northern Ireland Secretary Chris Heaton-Harris said the conditions were not met for a ballot on Irish unity.
With permission, I will make a statement on Northern Ireland Executive formation.
An estimated 170,000 public sector workers took part in a strike over pay last week.
The extension will provide more time as the DUP is yet to decide whether to return to power sharing.
There was no sign of the Northern Ireland Secretary as strikers chanted slogans outside the NIO office in Belfast city centre.
Schools will be closed and hospitals operating reduced services, while the Department for Infrastructure has advised against any unnecessary travel
An estimated 150,000 workers from sectors including education, health, police staff and transport will take part in the walkouts over a pay award.
"It is disappointing that there will not be a new Executive up and running to take up this offer and deliver it for the people of Northern Ireland before Christmas"
Northern Ireland Secretary Chris Heaton-Harris also unveiled a £3.3bn financial package to stabilise NI’s finances.