Sri Lanka on Sunday said the US should reconsider its decision to refuse entry to the island's army chief over his alleged war crimes and warned that relations were being "unnecessarily complicated".

The US Friday said the travel ban for Lieutenant General Shavendra Silva and his family was imposed over what it called credible evidence of human rights violations in the 2009 finale to the civil war.

US ambassador Alaina Teplitz was summoned by Sri Lanka's Foreign Minister Dinesh Gunawardena on Sunday, officials said.

He said Colombo was "disappointed" with the decision, the first against a Sri Lankan military officer.

"The minister said this action unnecessarily complicates the US-Sri Lanka relationship," his office said in a statement shortly after the closed-door meeting.

Silva was unfairly barred on unverified allegations, Gunawardena added.

The foreign ministry quoted Teplitz as saying the US would continue its cooperation with Sri Lanka, including in defence, despite the ban on Silva.

Silva's appointment in August sparked international outrage because of his links to alleged war crimes, and the UN briefly suspended the recruitment of Sri Lankan troops for peacekeeping duties.

Silva headed the army's 58th division in the final months of the battle against Tamil Tiger rebels. The military claimed victory in May 2009, but it also sparked allegations that up to 40,000 civilians were killed by troops.

There was no immediate comment from Teplitz or the US embassy in Colombo.