Gov. Bob McDonnell (R) said Tuesday that Senate Democrats and Republicans are busy negotiating new state legislative maps, but if they fail to reach a reasonable comprise he expects to veto a second bill.

Virginia Governor Bob McDonnell speaks at MicroAire Surgical Instruments, April 15, 2011 in Charlottesville. (AP Photo/The Daily Progress, Sabrina Schaeffer) (Sabrina Schaeffer/AP)

McDonnell said he met with Senate Democrats and Republicans separately Monday. Legislators negotiated late into the night Monday, and began again Tuesday morning.

“Look I’m optimistic,’’ McDonnell said. “They’ll work together to find a way to get this done — a legal and equitable bill that I can sign.”

The House and Senate earlier this month approved maps that reflect population shifts based on the 2010 census, as they are required to do every every decade after the census.

The House approved the plan in an 86 to 8 vote, with most Democrats voting in favor. The Senate adopted the bill on a straight party-line vote of 22 to 18.

McDonnell vetoed the bill, saying legislators had sent him maps that might violate state and federal laws, and split too many counties, cities and towns. The move angered House Republicans.

“The question isn’t whether they are happy but what is the right thing to do — whether I can sign a bill that is legal or not,’’ McDonnell said. “I don’t have a choice to pick between the House Republicans and the Democrat bill. I have one bill. I have to make one decision on that on balance. Of course, the House Republicans would have loved for me to sign the bill but I can’t do that in good faith.”

The House and Senate agreed to vote for their own plans and then each other’s as part of a deal between the chambers’ leaders. In past redistricting years, the chambers were controlled by the same party, and each passed its own bill.

“It’s one consolidated bill,’’ McDonnell said. “Now look, I think we are going to get there this week. And I told them I expect them to be working tirelessly this week. The clock is ticking... There are people of good will sitting down this week, as we speak, in Richmond, and talking about this.”