(Corrects Tran Thanh Man's age to 61, not 58, in paragraph 7)

HANOI, May 18 (Reuters) - Vietnam's Communist Party has named police minister To Lam as the state president, the government said on Saturday, and also nominated a new head of the parliament in a major leadership reshuffle.

Unprecedentedly for one-party nation once known for its stable politics, two state presidents and a parliament speaker have stepped down in less than 18 months, all for unspecified "wrongdoing" amid a major anti-graft campaign which is unnerving foreign investors because of its chilling effect on bureaucracy.

After approval from parliament, which could come next week, General Lam, 66, will replace Vo Van Thuong, who stepped down in March after being accused of violating party rules, just over a year after his appointment.

Widely considered one of the most powerful figures in the country, Lam was chosen by the party's Central Committee earlier this week, but authorities and state media revealed the nomination only on Saturday.

The president holds a largely ceremonial role but is one of the top four political positions. The others are the party chief, the prime minister and the parliament speaker.

Many observers see his appointment as a possible step towards becoming party chief, the country's top job, when current terms for leadership posts end in 2026 - or even earlier, if the aging general secretary Nguyen Phu Trong steps down before his third mandate expires.

The party also named Tran Thanh Man as the new chairman of the National Assembly, replacing Vuong Dinh Hue, who resigned last month over "violations and shortcomings." Man, 61, has served as deputy chairman of the parliament since 2021.

The nominations of Lam and Man came as the party named four new members of the Politburo on Thursday, the country's top decision-making body, after removing its fifth-ranking leader Truong Thi Mai from the group, the sixth to leave the Politburo since late 2022 in the unprecedented series of high-level resignations.

GOLD STEAK

Lam, a career police officer, has been Minister of Public Security since 2016 and was admitted to the Politburo in 2021.

He has also been deputy head of the party's anti-corruption steering committee since 2021, playing a crucial role in the anti-graft campaign that has seen thousands of officials and high-profile corporate executives prosecuted or forced to step down.

His rise has not been without controversy.

In 2021, celebrity chef "Salt Bae" uploaded a video of himself feeding To Lam a gold encrusted steak at his London restaurant while Vietnam was under COVID-19 lockdown. The video went viral before the Turkish chef Nusret Gokce removed it.

A noodle vendor who later posted a video imitating "Salt Bae" was sentenced to five years in prison for "anti-state propaganda."

Lam was the head of the public security ministry when in 2017 Vietnam's security services allegedly carried out an extraordinary rendition of a Vietnamese business executive from Germany through Slovakia. The case rattled relations with both countries. (Reporting by Khanh Vu, Phuong Nguyen and Francesco Guarascio; Editing by Giles Elgood)