The wife of Guatemalan President Jimmy Morales will be investigated on suspicion of cashing illicit checks made out to her and her husband totaling more than $30,000, the country's top prosecutor said on Friday.

Four checks were written out by a business also being investigated for corruption to first lady Patricia Marroquin de Morales and Jimmy Morales during his 2015 election campaign and later cashed, according to a local media report published on Thursday.

"We've begun the investigation," said Consuelo Porras, Guatemala's attorney general, in brief comments following an event in the capital Guatemala City.

The company that issued the checks, Fulanos & Menganos, is a restaurant owned by Othmar Sanchez, a friend of the president who also serves as a member of the Central American Parliament.

Alfredo Brito, a spokesman for the president's office, said in a statement that the executive is monitoring the investigation into the first lady and that it respects Guatemala's justice system.

"We reiterate our confidence in the objectivity and impartiality of the investigating agency in the application of justice in our country," he said.

Morales' government has been dogged by several corruption scandals since he took office in 2016 pledging to crack down on graft.

During his administration, the United Nations-backed International Commission Against Impunity in Guatemala (CICIG) repeatedly tried to strip Morales of his immunity from prosecution over allegations of campaign finance violations.

In 2015, a CICIG-led probe brought down Morales' predecessor, who is under arrest and on trial for corruption.

Morales hit back against the CICIG, accusing it of trying to destabilize Guatemala. In August he said he would not renew the organization's mandate, which is due to expire in September.