From conspiracies to action, television series based on spy stories have long been a popular genre on China's small screen.

But at a recent seminar to discuss the genre's prospects, some scriptwriters say it needs changes to survive in China's rapidly evolving entertainment industry.

Last year, only three of the 50 top-rated TV dramas were espionage tales. The rest were fantasy romances, according to a report by the entertainment researcher Entgroup.

Song Fangjin, known for penning the hit series Cellphone, says spy-themed dramas began to take off in 2004, when crime series saw an abrupt slump.

Espionage dramas first hit a peak in 2009 with Lurk, a suspenseful tale about a spy couple in 1945, and hit a new high in 2015 with The Disguiser, set in Shanghai after it was occupied by Japanese invaders in 1937.

But, despite the high ratings, the series were panned for the way they dealt with history and made revolutionary heroes look like pop idols.

"No matter how viewers' tastes change, they will never reject an appealing story," Song says.

He suggests Chinese scriptwriters also put aside their blind enthusiasm for programs bonded to intellectual property and shift their focus to works they are really interested in, or at least adept at.

IP, a Chinese concept which goes beyond the original abbreviation of intellectual property, refers to franchises developed from content such as online novels.

The concept thrived a couple of years ago with investors believing that only such productions could spell success.

Author Yuan Zidan echoes Song, saying her personal experiences sparked her passion to write the series Ode to Joy about women's lives, which topped TV ratings earlier last year.

Meanwhile, many scriptwriters say the recent success of Spy Game, an espionage hit, may put the genre back on track.

The 48-episode series, a Chinese answer to the American film Mr & Mrs Smith, is the most popular espionage series currently. It's broadcast by Shanghai-based Dragon TV and Beijing Satellite TV since March 20.

Yu Fei, who wrote the Spy Game, says his studio learned from its Hollywood counterparts about narration and pace.

"We first built the story. Then I divided the plotlines into sections, assigning them to writers," says Yu, adding that the process maximized creativity.

Screenwriter Wang Hailin says the most important element in a successful espionage story is to convince audience about the protagonist.

"After all, a spy's jobs include stealing and cheating, which violates regular morality," says Wang.

"You need to persuade the viewers that the character has no choice but to risk his life to win a battle without gunfire."