WASHINGTON — Veterans Affairs Secretary Eric Shinseki says he welcomes a White House review of his beleaguered department if it can help ensure veterans have access to timely, quality health care.

Shinseki was to go before a Senate committee today to address allegations of treatment delays and preventable deaths at a Phoenix veterans hospital.

Shinseki and other witnesses were expected to testify about allegations that the Phoenix hospital maintained a secret waiting list to hide lengthy delays for sick veterans. A former clinic director says up to 40 veterans may have died while awaiting treatment at the facility.

“If allegations about manipulation of appointment scheduling are true, they are completely unacceptable — to veterans, to me and to our dedicated VA employees,” Shinseki said.

The hearing before the Senate Veterans Affairs Committee comes as President Barack Obama has assigned White House deputy chief of staff Rob Nabors to work on a review focused on policies for patient safety rules and the scheduling of patient appointments. The move, announced late Wednesday, signals Obama’s growing concern over problems at the VA. Problems similar to those that surfaced in Phoenix have since been reported in other states.

The American Legion and some congressional Republicans have called for Shinseki to resign, a move he and the White House have resisted. The VA’s inspector general is investigating the Phoenix claims, and Shinseki has ordered an audit of VA facilities nationwide to see how they provide care.

A White House official said Shinseki requested more help with the review, leading Obama’s chief of staff, Denis McDonough, to tap Nabors for the assignment. Shinseki said he welcomed Nabors’ help in making sure veterans receive high-caliber health care in a timely fashion.